For many of these controversial ingredients, the FDA claims that the amount in products is not significant enough to actually do any harm, but with breast cancer rates up higher than ever, you can never be too safe.

1. Permanent and Semi-Permanent Hair Dyes (Especially Darker Colors)

Several studies have linked longtime hair dye use to bladder cancer, non-Hodgkin’s lymphoma, and multiple myeloma. Researchers found that rodents that were fed these compounds from coal-tar in certain hair dyes were more likely to develop cancer than rodents that were not fed these compounds. Read more about it here.

Scary Scientific Fact: If you’ve dyed your hair with a compound henna hair product, you should wait at least a year or two before re-dyeing with any kind of chemical hair dye containing hydrogen peroxide. According to HennaForHair.com, your hair “may turn frog butt green or offshore sewage outlet black.” The chemical reaction could also cause your hair to SMOKE and emit a foul odor.

How To Avoid:Do a strand test by taking some of your henna-dyed hair from a hairbrush and testing the chemical dye over it. If something catastrophic happens, then you know you’ve got metallic salts in your henna.

3. Aluminum Powder in Highly Pigmented Eyeshadows and Eyeliner

It’s found in popular products like Nars eyeshadow, Urban Decay 24/7 Glide-On eye pencil, and Yves Saint Laurent’s Everlong waterproof mascara. According to the Environmental Working Group, aluminum powder allegedly shows strong linkage to neurotoxicity and cancer. However, the FDA has deemed it safe as an ingredient in cosmetics.

4. Vitamin A in Sunscreen

Government data shows that an ingredient called retinyl palmitate, or vitamin A palmitate (used in over half of sunscreens available on the market) causes cancer on skin exposed to sunlight. Retinol (an animal form of vitamin A) is specifically used in night creams because it should never be applied during the day.*

Scary Scientific Fact: Lab animals covered in a retinol-laced skin cream and exposed to just nine minutes of sunlight every day for a year developed tumors and lesions up to 21% sooner than animals coated in vitamin A-free block.**

5. Nail Polish

You’re probably aware of the toxicity of nail polish by the fumes, the flammability, and the fact that you should always apply nail polish in a well-ventilated area. The three offending chemicals are: dibutyl phthalate (DBP), toluene, and formaldehyde. Despite the fact that many big-name nail polishes have agreed to remove the “Toxic Three,” tests show that a majority of them still contain the dangerous chemicals.

Scary Fact:Researchers who tested 33 nail salon workers found that they performed significantly worse on tests that measured attention and brain-processing speed. Maybe you aren’t exposed to as many fumes as they are, but if you’re pregnant or nursing, the chemicals inhaled could result in an actual effect on your child’s mental development.

6. Perfumes

The average mainstream perfume product might contain up to 14 secret ingredients, but due to a loophole in the Federal Fair Packaging and Labeling Act of 1973, perfume brands are not required to list them. Some common perfume ingredients are chemicals that have been associated with hormone disruption and allergic reactions. Many of these chemicals have also not been tested for safety.

Scary Fact: Secondhand scent might be considered the next secondhand smoke. Smelly people who apply too much cologne or perfume can trigger asthma, migraines, and nausea in those with chemical sensitivities. Some lawmakers and employers are even considering perfume bans.

How To Avoid: Well, there are always indie perfumes made from essential oils instead of industrial chemicals. And you should also probably avoid any product that has the generic umbrella term “fragrance” in its ingredient list. This sadly rules out pretty much every nice-smelling product you own. Goodbye, St. Ives Apricot Scrub and Chanel face cream.

Scary Story: “Salon workers and consumers have reported a number of injuries to the FDA due to use of the products, including eye and nervous system disorders, respiratory tract problems, chest pain, vomiting, and rash,” according to WebMD.

How To Avoid: Watch out for an ingredient called “methylene glycol,” which is basically just formaldehyde mixed with water. It’s how companies get away with calling their products “formaldehyde-free.”

Sad But True Fact: Many of the “natural” and “eco” products sold in drugstores or at your local Sephora are owned by giant companies like Colgate, L’Oréal, and Estée Lauder. These are the same companies that put lead in their lipsticks and triclosan in their toothpaste (which has been known to alter hormone regulation in animal studies).

Interesting Fact: “The Government of Canada has implemented numerous measures to reduce the amount of heavy metals to which Canadians are exposed, including prohibiting their use in cosmetics. Lead, arsenic, cadmium, mercury, antimony and chromium are heavy metal ingredients prohibited in cosmetics sold in Canada.” Click here for a much more detailed explanation of the harms of heavy metals in cosmetics.

How To Avoid: If you don’t want to wear synthetic chemicals and you don’t want microscopic metals permeating through your skin, you’re probably just better off not wearing any makeup at all.

Scary Scientific Fact: If you shave your armpits (increasing the chance of nicks and skin breakage) AND use anti-perspirant, you could be at higher risk. See the study here and here.

How To Avoid: There are many natural deodorants on the market which have very low toxicity scores on the EWG Skin Deep database. Unfortunately, many chronic perspirers claim the natural stuff just doesn’t work for them.